Plasma membrane H+ pump at a crossroads of acidic and iron stresses in yeast-to-hypha transition. Issue 12 (15th December 2020)

• Record Type: Journal Article
• Authors: Cogo, Antônio Jesus Dorighetto; Façanha, Arnoldo Rocha; da Silva Teixeira, Layz Ribeiro; de Souza, Sávio Bastos; da Rocha, Janiélio Gonçalves; Figueira, Frederico Firme; Eutrópio, Frederico Jacob; Bertolazi, Amanda Azevedo; de Rezende, Carlos Eduardo; Krohling, Cesar Abel; Okorokov, Lev A.; Cruz, Cristina; Ramos, Alessandro Coutinho; Okorokova-Façanha, Anna L.
• Is Part Of: Metallomics. Volume 12:Issue 12(2020)
• Page Start: 2174
• Page End: 2185
• Publication Date: 2020-12-15
• Subjects: Metals -- Physiological effect -- Periodicals; 572.51
• DOI: 10.1039/d0mt00179a
• Languages: English
• ISSNs: 1756-5901

Abstract

Abstract : Proposed model for iron- and pH-induced stress responses in Y. lipolytica, highlighting the PM H + -pumps modulation and the pH-dependent enzymes, integrated by the Ras2- and Rim101 pathways regulating the polarized cell growth and filamentation. Abstract : Iron is an essential nutrient but is toxic in excess mainly under acidic conditions. Yeasts have emerged as low cost, highly efficient soil inoculants for the decontamination of metal-polluted areas, harnessing an increasing understanding of their metal tolerance mechanisms. Here, we investigated the effects of extracellular iron and acid pH stress on the dimorphism of Yarrowia lipolytica . Its growth was unaffected by 1 or 2 mM FeSO4, while a strong cellular iron accumulation was detected. However, the iron treatments decreased the hyphal length and number, mainly at 2 mM FeSO4 and pH 4.5. Inward cell membrane H + fluxes were found at pH 4.5 and 6.0 correlated with a pH increase at the cell surface and a conspicuous yeast-to-hypha transition activity. Conversely, a remarkable H + efflux was detected at pH 3.0, related to the extracellular microenvironment acidification and inhibition of yeast-to-hypha transition. Iron treatments intensified H + influxes at pH 4.5 and 6.0 and inhibited H + efflux at pH 3.0. Moreover, iron treatments inhibited the expression and activities of the plasma membrane H + -ATPase, with the H + transport inhibited to a greater extent than the ATP hydrolysis, suggesting an iron-induced uncoupling of the pump. Our data indicate that Y. lipolytica adaptations to high iron and acidic environments occur at the expense of remodelling the yeast morphogenesis through a cellular pH modulation by H + -ATPases and H + coupled transporters, highlighting the capacity of this non-conventional yeast to accumulate high amounts of iron and its potential application for bioremediation.